Well...there is the terrorist thing.
And as to Obama, his leftist, wholly big government, socialistic/maxistic tendencies are more than enough for me to label him as another enemy to the basic value systems and innstitutions our republic rests on.
If that weren;t enough (and it most certainly is), then, for safety's sake, at a time when we are at war with abject muslim/islamic terrorists and those who support and abett them, I believe we would be foolish to elect a President who did attend muslim schools as a youth (regardless of the variety) named Hussein Obama. But that's just my own feeling and is no more hard to understand than being leary of any politician who had tried to be elected in 1942 named Tojo-san.
"that Muslim peoples are frequently stereotyped as ...particularly prone to violence and generally supportive of terrorism"